Now that the summer solstice has passed and the nights are getting longer, all thoughts will inevitably turn towards winter. Questions will be raised such as, will 2013/14 be repeated? Or will 2014/15 be cold and snowy.
Well let’s first look at why the 2013/14 winter turned out so persistently wet and windy. There have been strong suggestions that persistent Indonesian rainfall had a huge impact on the Pacific jet stream, causing the jet to buckle and allowing a dominant high pressure system to reside just off the Northwest coast of America and Canada. This in turn started to drag very cold air from the Artic, filtering down the eastern side of the USA and plunging these areas in to a very cold and bitter winter. Due to the eastern USA being unusually bitter, the cold temperatures caused a huge temperature contrast between the warm flow of the Atlantic Ocean (via the Gulf Stream) and the cold air mass filtering out of the USA. This contrast was partly responsible, along with an unusually strong QBO (Quasi-biennial oscillation) for a strengthening of the jet stream, which in turn strengthened the low pressures systems that affected the United Kingdom.
Another factor to consider is solar activity, although the science regarding this factor has only recently come to fruition, it’s possible that increased solar activity during the winter of 2013/14, probably due to the suns magnetic polar flip, was also partly responsible for the strengthening of the Atlantic jet. So a lot of factors it seems had to come together at just the right time to produce such a consistent flow of Atlantic depressions.
So will this be pattern be repeated in 2014/15? Well we don’t think so as it stands, partly because we have a devolving El Nino, which won’t guarantee a cold winter, but our winters during an El Niño tend to be drier than average. The last El Nino winter we experienced was 2009/10, which turned out to be a very cold winter, so the chances are that a repeat of 2013/14 will be very unlikely. There are some signals that this winter will possibly have some colder periods, however, this is not a given with this time frame but as ever we will keep you updated. Watch this space!!!!